JOAN Burton is the people's clear favourite to lead the Labour Party on a strict mandate to end austerity or pull out of Government, a Sunday Independent/Millward Brown opinion poll has found.

But over half of voters do not expect austerity to end and more believe the Government will collapse than believe it will last full term.

In a shock finding, Sinn Fein has surged ahead since the recent elections to become the most popular party in the country and, on this poll, can expect to lead a new coalition if the Government falls.

The poll findings will deliver another significant blow to the embattled Coalition parties, still reeling from the hammering they received at the ballot box during the local and European elections.

Last night, new Cabinet minister Charlie Flanagan warned a real danger existed that "the Coalition could stumble into an early election".

Mr Flanagan told the Sunday Independent: "We are still dealing with the local elections fall-out, the Cabinet reshuffle and the Labour leadership... there is quite a degree of turbulence in Government... It is critical that we are not blown off course by that turbulence."

Should the Government collapse, Sinn Fein (at 26 per cent) is firm favourite to lead a new coalition – with a range of potential partners. The nationwide survey, conducted on Tuesday and Wednesday last, shows that voters' attitudes have, if anything, hardened further since the recent elections to such an extent that it is now conceivable that a Sinn Fein-led hard Left Government may be elected for the first time.

According to the poll, a coalition of Fine Gael (20 per cent) and Fianna Fail (20 per cent) would be unable to secure a majority were a General Election to be called now.

On the brink of annihilation, the Labour leadership contest will take on greater significance in a dramatically altered political landscape.

The poll finds that Social Protection Minister Ms Burton (35 per cent) is more than twice as likely to attract voters to Labour than is her leadership rival, Minister of State Alex White (16 per cent). But between them, they appeal to only half the electorate.

Critically, almost three-quarters (71 per cent) of Labour supporters back Ms Burton for the leadership.

However, support for Ms Burton comes with a clear condition – end austerity or get out of Government. A massive 73 per cent said a new Labour leader, whichever candidate wins, should end the Government's austerity policy.

But more than half (53 per cent) do not expect the new leader to be successful – just 27 per cent believe austerity will end as a result of the leadership contest.

A similar majority (52 per cent) believe Labour should pull out of Government if the new leader does not achieve austerity policy change.

Just under a third of voters (30 per cent) believe Labour should stay in office if the new leader fails to end austerity, rising to 53 per cent of Fine Gael supporters – but only 38 per cent of Labour supporters say the party should stay in office without such change.

As a result, there is little faith that the Government will continue until 2016, according to the poll – only two in five expect the Coalition to go the full term.

Asked whether they believed the Coalition would last, 46 per cent said 'no', 40 per cent said 'yes', 10 per cent did not know and 3 per cent said it depended.

A Fianna Fail-Sinn Fein coalition (15 per cent) was most favoured by those polled, followed by Fianna Fail-Independents (11 per cent), Fine Gael-Labour (9 per cent), Fine Gael-Independents (9 per cent), Fine Gael-Sinn Fein (7 per cent) and Fine Gael-Fianna Fail (5 per cent).

A coalition option of Sinn Fein-Independents was not offered on this occasion, but from other poll findings it is possible that Sinn Fein (26 per cent) and Independents/ Others (27 per cent) could form a new coalition should an election be called.

The impending water charges have emerged as the most hated of all the Government's crippling austerity measures.

More than a third (37 per cent) of voters put the water levy on top of their wish list of taxes they want to see reversed, above cuts to discretionary medical cards (33 per cent) and the despised property tax (22 per cent).

Confirmation of the deep dissatisfaction over water charges will be viewed with alarm by the Government parties.

Anger at having to pay for water – coming on top of the property tax and the household charge – was a key factor behind the devastating collapse of Labour's vote and the loss of around 90 Fine Gael council seats in the recent elections.

For many, the country's love affair with Europe has ended in bitter acrimony –with one in four voters now saying Ireland should consider splitting from the EU and controlling our own economic destiny.